A prior art wax filter manipulator and wax filter is known from PCT publication No. WO 0003561 by Tøpholm & Westermann. The wax filter according to this document comprises an essentially tubular element adapted to the mouth diameter of the acoustic outlet passage or the vent and has a through-going cavity, which in one end is partially closed by an ear wax retaining guard. The element in the opposite end is connected to a surrounding abutment collar for sealing abutment against the hearing aid housing around the acoustic outlet port or vent. The element is made of an elastically yielding material and the through-going cavity at its mouth in the abutment collar is adapted for introduction of a means to be used when the ear wax guard is inserted in and removed from the acoustic outlet port or the vent. Typically silicone rubber or a thermoplastic elastomer is used for this known ear wax filter.
From the above document a manipulator for insertion and extraction of the described wax filter is known. The manipulator according to the document comprises an essentially rod-shaped applicator. In the one end the rod is provided with a smooth pin fitting the mouth of the through-going cavity of the wax filter for use at the insertion of the ear wax filter. In the opposite end the rod-shaped manipulator is provided with a catch member for use at removal of the wax filter and engaging the wall inner side of the through-going cavity when pressed into it. The catch member has a harpoon-shaped pressing-in peak projecting from the end surface thereof and further has catch edges for providing an engagement with the mouth of the through-going cavity in the wax filter.
The soft material of the prior art wax filter and the harpoon-shape of the pressing-in peak has the drawback that the user cannot determine when the pressing-in peak has reached a sufficient depth to draw out an old wax filter. The user is at risk of exerting a force which is too high, and thereby forcing the used filter further into the hearing aid. This may damage the hearing aid and also it is difficult to extract the filter from within the hearing aid. It is further a problem with the soft material that new filters some times fall out of the sound outlet orifice. Also, the process of extracting an old filter and inserting a new one demands that the user turn the rod shaped manipulator around in order to bring the new filter, which is positioned at the other end of the rod shaped applicator in position for insertion. This action is easily performed by most people, but as many hearing aid users are elderly, this operation could prove cumbersome and the applicator may be dropped or fall out of the hand during the turn around motion. Should the rod shaped applicator be dropped it might, due to its round shape roll along the floor and end under furniture or other objects, wherefrom it is only retrieved with difficulty.
Also a system comprising a number of applicators and filters of the above-described kind in a holder is known and sold by Widex®. The holder comprise a single array of holes wherein each hole accommodates one of the rod shaped applicators, such that a first end of the applicator is inserted into the hole and the other end is sticking out in order to be gripped by the user. It requires good eyesight and good dexterity to extract one single manipulator from the array of manipulators, as these are placed with parallel length axes adjacent each other in the array of holes. Not all hearing aid users have these skills. Further, if the user should inadvertently re-insert one of the applicators after use, there is nothing to prevent this insertion, and the user might at a later time erroneously try to insert the old wax filter from this used re-inserted applicator in his hearing aid.
It is the object of the invention to provide a filter, a filter manipulator and system comprising a number of applicators in a holder, which does not have the above draw backs. Such a filter, filter manipulator and system would be usable both for handling wax filter and for handling acoustic filters or microphone inlet filters.